[PATCH v8 16/30] KVM: selftests: TDX: Add TDX MSR read/write tests

[Sagi Shahar <sagis@google.com>]

The test verifies reads and writes for MSR registers with different access
level.

Signed-off-by: Sagi Shahar <sagis@google.com>
---
 .../selftests/kvm/include/x86/tdx/tdx.h       |   4 +
 tools/testing/selftests/kvm/lib/x86/tdx/tdx.c |  27 +++
 tools/testing/selftests/kvm/x86/tdx_vm_test.c | 193 +++++++++++++++++-
 3 files changed, 223 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
index 97ceb90c8792..56359a8c4c19 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
@@ -10,10 +10,14 @@
 #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
 
 #define TDG_VP_VMCALL_INSTRUCTION_IO 30
+#define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
+#define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
 
 uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
 				      uint64_t write, uint64_t *data);
 void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa);
 uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
 					  uint64_t *r13, uint64_t *r14);
+uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value);
+uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value);
 #endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
index 5105dfae0e9e..99ec45a5a657 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
@@ -66,3 +66,30 @@ uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
 
 	return ret;
 }
+
+uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_INSTRUCTION_RDMSR,
+		.r12 = index,
+	};
+	uint64_t ret;
+
+	ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+	if (ret_value)
+		*ret_value = args.r11;
+
+	return ret;
+}
+
+uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_INSTRUCTION_WRMSR,
+		.r12 = index,
+		.r13 = value,
+	};
+
+	return __tdx_hypercall(&args, 0);
+}
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
index ae5749e5c605..079ac266a44e 100644
--- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c
+++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
@@ -455,6 +455,193 @@ void verify_guest_reads(void)
 	printf("\t ... PASSED\n");
 }
 
+/*
+ * Define a filter which denies all MSR access except the following:
+ * MSR_X2APIC_APIC_ICR: Allow read/write access (allowed by default)
+ * MSR_IA32_MISC_ENABLE: Allow read access
+ * MSR_IA32_POWER_CTL: Allow write access
+ */
+#define MSR_X2APIC_APIC_ICR 0x830
+static u64 tdx_msr_test_allow_bits = ~0ULL;
+struct kvm_msr_filter tdx_msr_test_filter = {
+	.flags = KVM_MSR_FILTER_DEFAULT_DENY,
+	.ranges = {
+		{
+			.flags = KVM_MSR_FILTER_READ,
+			.nmsrs = 1,
+			.base = MSR_IA32_MISC_ENABLE,
+			.bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
+		}, {
+			.flags = KVM_MSR_FILTER_WRITE,
+			.nmsrs = 1,
+			.base = MSR_IA32_POWER_CTL,
+			.bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
+		},
+	},
+};
+
+/*
+ * Verifies MSR read functionality.
+ */
+void guest_msr_read(void)
+{
+	uint64_t data;
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_X2APIC_APIC_ICR, &data);
+	tdx_assert_error(ret);
+
+	ret = tdx_test_report_64bit_to_user_space(data);
+	tdx_assert_error(ret);
+
+	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_MISC_ENABLE, &data);
+	tdx_assert_error(ret);
+
+	ret = tdx_test_report_64bit_to_user_space(data);
+	tdx_assert_error(ret);
+
+	/* Expect this call to fail since MSR_IA32_POWER_CTL is write only */
+	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_POWER_CTL, &data);
+	if (ret) {
+		ret = tdx_test_report_64bit_to_user_space(ret);
+		tdx_assert_error(ret);
+	} else {
+		tdx_test_fatal(-99);
+	}
+
+	tdx_test_success();
+}
+
+void verify_guest_msr_reads(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	uint64_t data;
+	int ret;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+
+	/*
+	 * Set explicit MSR filter map to control access to the MSR registers
+	 * used in the test.
+	 */
+	printf("\t ... Setting test MSR filter\n");
+	ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
+	TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
+
+	ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
+	TEST_ASSERT(ret == 0,
+		    "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
+		    ret, errno, strerror(errno));
+
+	vcpu = td_vcpu_add(vm, 0, guest_msr_read);
+	td_finalize(vm);
+
+	printf("Verifying guest msr reads:\n");
+
+	printf("\t ... Setting test MSR values\n");
+	/* Write arbitrary to the MSRs. */
+	vcpu_set_msr(vcpu, MSR_X2APIC_APIC_ICR, 4);
+	vcpu_set_msr(vcpu, MSR_IA32_MISC_ENABLE, 5);
+	vcpu_set_msr(vcpu, MSR_IA32_POWER_CTL, 6);
+
+	printf("\t ... Running guest\n");
+	tdx_run(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, 4);
+
+	tdx_run(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, 5);
+
+	tdx_run(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
+
+	tdx_run(vcpu);
+	tdx_test_assert_success(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
+/*
+ * Verifies MSR write functionality.
+ */
+void guest_msr_write(void)
+{
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_X2APIC_APIC_ICR, 4);
+	tdx_assert_error(ret);
+
+	/* Expect this call to fail since MSR_IA32_MISC_ENABLE is read only */
+	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_MISC_ENABLE, 5);
+	if (ret) {
+		ret = tdx_test_report_64bit_to_user_space(ret);
+		tdx_assert_error(ret);
+	} else {
+		tdx_test_fatal(-99);
+	}
+
+	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_POWER_CTL, 6);
+	tdx_assert_error(ret);
+
+	tdx_test_success();
+}
+
+void verify_guest_msr_writes(void)
+{
+	uint64_t ia32_misc_enable_val;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	uint64_t data;
+	int ret;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+
+	/*
+	 * Set explicit MSR filter map to control access to the MSR registers
+	 * used in the test.
+	 */
+	printf("\t ... Setting test MSR filter\n");
+	ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
+	TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
+
+	ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
+	TEST_ASSERT(ret == 0,
+		    "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
+		    ret, errno, strerror(errno));
+
+	vcpu = td_vcpu_add(vm, 0, guest_msr_write);
+	td_finalize(vm);
+
+	ia32_misc_enable_val = vcpu_get_msr(vcpu, MSR_IA32_MISC_ENABLE);
+
+	printf("Verifying guest msr writes:\n");
+
+	printf("\t ... Running guest\n");
+	/* Only the write to MSR_IA32_MISC_ENABLE should trigger an exit */
+	tdx_run(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
+
+	tdx_run(vcpu);
+	tdx_test_assert_success(vcpu);
+
+	printf("\t ... Verifying MSR values written by guest\n");
+
+	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_X2APIC_APIC_ICR), 4);
+	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_MISC_ENABLE),
+		       ia32_misc_enable_val);
+	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_POWER_CTL), 6);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
 int main(int argc, char **argv)
 {
 	ksft_print_header();
@@ -462,7 +649,7 @@ int main(int argc, char **argv)
 	if (!is_tdx_enabled())
 		ksft_exit_skip("TDX is not supported by the KVM. Exiting.\n");
 
-	ksft_set_plan(7);
+	ksft_set_plan(9);
 	ksft_test_result(!run_in_new_process(&verify_td_lifecycle),
 			 "verify_td_lifecycle\n");
 	ksft_test_result(!run_in_new_process(&verify_report_fatal_error),
@@ -477,6 +664,10 @@ int main(int argc, char **argv)
 			 "verify_guest_writes\n");
 	ksft_test_result(!run_in_new_process(&verify_guest_reads),
 			 "verify_guest_reads\n");
+	ksft_test_result(!run_in_new_process(&verify_guest_msr_writes),
+			 "verify_guest_msr_writes\n");
+	ksft_test_result(!run_in_new_process(&verify_guest_msr_reads),
+			 "verify_guest_msr_reads\n");
 
 	ksft_finished();
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog